The invention relates to electric switches in general, and more particularly to improvements in so-called pushbutton switches wherein a mobile member (such as a plunger) is depressible from an extended or inoperative position to a depressed or operative position and is normally biased to the extended position. Still more particularly, the invention relates to improvements in convertible pushbutton switches of the type capable of operating as so-called momentary switches or as so-called latching or alternate-action switches. A momentary switch is designed to complete one or more circuits as long as its mobile member remains depressed; however, the circuit or circuits are interrupted as soon as the pressure upon the mobile member is relaxed or terminated. An alternate-action or latching switch operates in such a way that an initial depression of the mobile member results in completion of one or more circuits and such circuit or circuits remain completed when the pressure upon the depressed mobile member is relaxed or terminated. Opening of the circuit or circuits necessitates a renewed (second) depression of the mobile member.
Convertible momentary and latching switches are disclosed, for example, in U.S. Pats. Nos. 4,242,544 and 4,242,545, and in Swiss Pat. No. 595,687. An advantage of such switches is that the manufacturer need not supply two different sets of switches, namely a first set acting only as momentary switches and a second set acting only as latching switches.
The switch which is disclosed in Swiss Pat. No. 595,687 has two cams and a single follower which can be transferred from a first position, in which it cooperates with one of the cams and the switch acts as a momentary switch, to a second position in which the follower cooperates with the other cam and the switch acts as a latching switch. A drawback of such switches is that transfer of the follower from one position to the other position necessitates complete separation of the follower from the remaining parts of the switch. Moreover, the follower and the cam are very small if the switch is a microswitch so that it is difficult to see the momentary position of the follower without a magnifying glass, and the transfer of such minute follower from one to the other position is a tedious and time-consuming operation. The making of two discrete cams contributes to the initial cost of the switch, and the two cams occupy a substantial amount of space. Still further, the follower must be readily accessible for repeated detachment from and for repeated reattachment to other parts of the switch.